Divide file contents and read from threads

Question

I am reading a file which contains doubles... I can do this with 1 thread.
Now I want to use 2 threads and make each thread read half of that file.. How do I make file to half .. If I take the length and divide by two wont it destort the doubles?
public class SingleThread extends Thread
     /*** Constructor ***/
     public SingleThread(){}
     /*** Run the thread ***/
     public void run()
          try{
          FileInputStream fis = new FileInputStream("File1.bin");
          DataInputStream dis = new DataInputStream(fis);
          int size = fis.available();
          System.out.println("Size of File1 "+size);
          /*Create an array that can store 100,000 numbers*/
          double num1[] = new double[100001];
          /*Get random number*/
          for (int count = 0; count <= 100000; count ++)
               num1[count] = dis.readDouble();
               System.out.println(count); //Count
               System.out.println(num1[count]); //Prints doubles that are read from file.
     }//try
          catch(Exception e){System.out.println("Exception: "+e.getMessage());}
     /******************** Main Program ********************************************************/
     public static void main(String[] args)
          new SingleThread().start();
}

Answer 1

I dont know....my professor wants us to test multithreading response times.. :(